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Commit a79caa33 authored by Zach Johnson's avatar Zach Johnson
Browse files

Special case & sanitize exposure notification results 

Bug: 162031802
Tag: #feature
Test: verified do not get results before this change,
      and after the change, get results but only the
      RSSI & payload for EN

Change-Id: I9dca7d398ecc1543fc001921deb95c07b1b84e15
parent ca1b527e

res/values/config.xml

+3 −0
Original line number Diff line number Diff line
@@ -114,4 +114,7 @@ 
    <!-- Flag whether or not to keep polling AG with CLCC for call information every 2 seconds -->

    <bool name="hfp_clcc_poll_during_call">true</bool>



    <!-- Package that is providing the exposure notification service -->

    <string name="exposure_notification_package">com.google.android.gms</string>



</resources>

src/com/android/bluetooth/gatt/ContextMap.java

+2 −0
Original line number Diff line number Diff line
@@ -107,6 +107,8 @@ import java.util.UUID; 
        /** Whether the calling app has the network setup wizard permission */

        boolean mHasScanWithoutLocationPermission;



        boolean mEligibleForSanitizedExposureNotification;



        public List<String> mAssociatedDevices;



        /** Internal callback info queue, waiting to be send on congestion clear */

src/com/android/bluetooth/gatt/GattService.java

+68 −0
Original line number Diff line number Diff line
@@ -56,6 +56,7 @@ import android.os.ServiceManager; 
import android.os.SystemClock;

import android.os.UserHandle;

import android.os.WorkSource;

import android.provider.Settings;

import android.util.Log;



import com.android.bluetooth.BluetoothMetricsProto;
@@ -185,6 +186,7 @@ public class GattService extends ProfileService { 
    private ScanManager mScanManager;

    private AppOpsManager mAppOps;

    private ICompanionDeviceManager mCompanionManager;

    private String mExposureNotificationPackage;



    private static GattService sGattService;
@@ -207,6 +209,9 @@ public class GattService extends ProfileService { 
        if (DBG) {

            Log.d(TAG, "start()");

        }

        mExposureNotificationPackage = getString(R.string.exposure_notification_package);

        Settings.Global.putInt(

                getContentResolver(), "bluetooth_sanitized_exposure_notification_supported", 1);

        initializeNative();

        mAdapter = BluetoothAdapter.getDefaultAdapter();

        mCompanionManager = ICompanionDeviceManager.Stub.asInterface(
@@ -960,6 +965,56 @@ public class GattService extends ProfileService { 
     * Callback functions - CLIENT

     *************************************************************************/



    // EN format defined here:

    // https://blog.google/documents/70/Exposure_Notification_-_Bluetooth_Specification_v1.2.2.pdf

    private static final byte[] EXPOSURE_NOTIFICATION_FLAGS_PREAMBLE = new byte[] {

        // size 2, flag field, flags byte (value is not important)

        (byte) 0x02, (byte) 0x01

    };

    private static final int EXPOSURE_NOTIFICATION_FLAGS_LENGTH = 0x2 + 1;

    private static final byte[] EXPOSURE_NOTIFICATION_PAYLOAD_PREAMBLE = new byte[] {

        // size 3, complete 16 bit UUID, EN UUID

        (byte) 0x03, (byte) 0x03, (byte) 0x6F, (byte) 0xFD,

        // size 23, data for 16 bit UUID, EN UUID

        (byte) 0x17, (byte) 0x16, (byte) 0x6F, (byte) 0xFD,

        // ...payload

    };

    private static final int EXPOSURE_NOTIFICATION_PAYLOAD_LENGTH = 0x03 + 0x17 + 2;



    private static boolean arrayStartsWith(byte[] array, byte[] prefix) {

        if (array.length < prefix.length) {

            return false;

        }

        for (int i = 0; i < prefix.length; i++) {

            if (prefix[i] != array[i]) {

                return false;

            }

        }

        return true;

    }



    ScanResult getSanitizedExposureNotification(ScanResult result) {

        ScanRecord record = result.getScanRecord();

        // Remove the flags part of the payload, if present

        if (record.getBytes().length > EXPOSURE_NOTIFICATION_FLAGS_LENGTH

                && arrayStartsWith(record.getBytes(), EXPOSURE_NOTIFICATION_FLAGS_PREAMBLE)) {

            record = ScanRecord.parseFromBytes(

                    Arrays.copyOfRange(

                            record.getBytes(),

                            EXPOSURE_NOTIFICATION_FLAGS_LENGTH,

                            record.getBytes().length));

        }



        if (record.getBytes().length != EXPOSURE_NOTIFICATION_PAYLOAD_LENGTH) {

            return null;

        }

        if (!arrayStartsWith(record.getBytes(), EXPOSURE_NOTIFICATION_PAYLOAD_PREAMBLE)) {

            return null;

        }



        return new ScanResult(null, 0, 0, 0, 0, 0, result.getRssi(), 0, record, 0);

    }



    void onScanResult(int eventType, int addressType, String address, int primaryPhy,

            int secondaryPhy, int advertisingSid, int txPower, int rssi, int periodicAdvInt,

            byte[] advData) {
@@ -1027,6 +1082,13 @@ public class GattService extends ProfileService { 
                    }

                }

            }

            if (!hasPermission && client.eligibleForSanitizedExposureNotification) {

                ScanResult sanitized = getSanitizedExposureNotification(result);

                if (sanitized != null) {

                    hasPermission = true;

                    result = sanitized;

                }

            }

            if (!hasPermission || !matchesFilters(client, result)) {

                continue;

            }
@@ -1986,6 +2048,8 @@ public class GattService extends ProfileService { 
        final ScanClient scanClient = new ScanClient(scannerId, settings, filters, storages);

        scanClient.userHandle = UserHandle.of(UserHandle.getCallingUserId());

        mAppOps.checkPackage(Binder.getCallingUid(), callingPackage);

        scanClient.eligibleForSanitizedExposureNotification =

                callingPackage.equals(mExposureNotificationPackage);

        scanClient.isQApp = Utils.isQApp(this, callingPackage);

        if (scanClient.isQApp) {

            scanClient.hasLocationPermission = Utils.checkCallerHasFineLocation(this, mAppOps,
@@ -2046,6 +2110,8 @@ public class GattService extends ProfileService { 
        ScannerMap.App app = mScannerMap.add(uuid, null, null, piInfo, this);

        app.mUserHandle = UserHandle.of(UserHandle.getCallingUserId());

        mAppOps.checkPackage(Binder.getCallingUid(), callingPackage);

        app.mEligibleForSanitizedExposureNotification =

                callingPackage.equals(mExposureNotificationPackage);

        app.mIsQApp = Utils.isQApp(this, callingPackage);

        try {

            if (app.mIsQApp) {
@@ -2076,6 +2142,8 @@ public class GattService extends ProfileService { 
        scanClient.hasLocationPermission = app.hasLocationPermission;

        scanClient.userHandle = app.mUserHandle;

        scanClient.isQApp = app.mIsQApp;

        scanClient.eligibleForSanitizedExposureNotification =

                app.mEligibleForSanitizedExposureNotification;

        scanClient.hasNetworkSettingsPermission = app.mHasNetworkSettingsPermission;

        scanClient.hasNetworkSetupWizardPermission = app.mHasNetworkSetupWizardPermission;

        scanClient.hasScanWithoutLocationPermission = app.mHasScanWithoutLocationPermission;

src/com/android/bluetooth/gatt/ScanClient.java

+1 −0
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ import java.util.UUID; 
    public boolean hasLocationPermission;

    public UserHandle userHandle;

    public boolean isQApp;

    public boolean eligibleForSanitizedExposureNotification;

    public boolean hasNetworkSettingsPermission;

    public boolean hasNetworkSetupWizardPermission;

    public boolean hasScanWithoutLocationPermission;